IEEE80211_INPUT(9)					   BSD Kernel Developer's Manual					IEEE80211_INPUT(9)

NAME

     ieee80211_input -- software 802.11 stack input functions

SYNOPSIS

     #include <net80211/ieee80211_var.h>

     void
     ieee80211_input(struct ieee80211_node *, struct mbuf *, int rssi, int noise);

     void
     ieee80211_input_all(struct ieee80211com *, struct mbuf *, int rssi, int noise);

DESCRIPTION

     The net80211 layer that supports 802.11 device drivers requires that receive processing be single-threaded.  Typically this is done using a
     dedicated driver taskqueue(9) thread.  ieee80211_input() and ieee80211_input_all() process received 802.11 frames and are designed for use in
     that context; e.g. no driver locks may be held.

     The frame passed up in the mbuf must have the 802.11 protocol header at the front; all device-specific information and/or PLCP must be
     removed.  Any CRC must be stripped from the end of the frame.  The 802.11 protocol header should be 32-bit aligned for optimal performance
     but receive processing does not require it.  If the frame holds a payload and that is not aligned to a 32-bit boundary then the payload will
     be re-aligned so that it is suitable for processing by protocols such as ip(4).

     If a device (such as ath(4)) inserts padding after the 802.11 header to align the payload to a 32-bit boundary the IEEE80211_C_DATAPAD capa-
     bility must be set.  Otherwise header and payload are assumed contiguous in the mbuf chain.

     If a received frame must pass through the A-MPDU receive reorder buffer then the mbuf must be marked with the M_AMPDU flag.  Note that for
     the moment this is required of all frames received from a station and TID where a Block ACK stream is active, not just A-MPDU aggregates.	It
     is sufficient to check for IEEE80211_NODE_HT in the ni_flags of the station's node table entry, any frames that do not require reorder pro-
     cessing will be dispatched with only minimal overhead.

     The rssi parameter is the Receive Signal Strength Indication of the frame measured in 0.5dBm units relative to the noise floor.  The noise
     parameter is the best approximation of the noise floor in dBm units at the time the frame was received.  RSSI and noise are used by the
     net80211 layer to make scanning and roaming decisions in station mode and to do auto channel selection for hostap and similar modes.  Other-
     wise the values are made available to user applications (with the rssi presented as a filtered average over the last ten values and the noise
     floor the last reported value).

SEE ALSO

     ieee80211(9)

BSD
								  August 4, 2009							       BSD